From 4decd584983249b8d89cbef93556c973506428ed Mon Sep 17 00:00:00 2001
From: Philip Norton <philip@adam.co.za>
Date: Thu, 5 Nov 2026 10:43:16 +0200
Subject: [PATCH 1/2] [NodeTypeResolver] Set scope on the class name of a
 first-class callable

processCallLike() returned early for every first-class callable, which
left the class name of self::method(...) and static::method(...) without
a scope. NameTypeResolver needs that scope to resolve self and static, so
it returned an ObjectType for a class literally named "self" or "static".

RemoveUnusedPrivateMethodParameterRector could then not match the callable
to its class, missed the isFirstClassCallable() guard and removed a
parameter from a method whose arity the receiving code controls.

The early return only has to protect getArgs(), so it moves back below the
scope assignments, where it was before #8793.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
---
 .../skip_with_first_class_callable_self.php.inc  | 16 ++++++++++++++++
 ...lass_callable_self_in_instance_method.php.inc | 16 ++++++++++++++++
 ...skip_with_first_class_callable_static.php.inc | 16 ++++++++++++++++
 .../PHPStan/Scope/PHPStanNodeScopeResolver.php   |  8 ++++----
 4 files changed, 52 insertions(+), 4 deletions(-)
 create mode 100644 rules-tests/DeadCode/Rector/ClassMethod/RemoveUnusedPrivateMethodParameterRector/Fixture/skip_with_first_class_callable_self.php.inc
 create mode 100644 rules-tests/DeadCode/Rector/ClassMethod/RemoveUnusedPrivateMethodParameterRector/Fixture/skip_with_first_class_callable_self_in_instance_method.php.inc
 create mode 100644 rules-tests/DeadCode/Rector/ClassMethod/RemoveUnusedPrivateMethodParameterRector/Fixture/skip_with_first_class_callable_static.php.inc

diff --git a/rules-tests/DeadCode/Rector/ClassMethod/RemoveUnusedPrivateMethodParameterRector/Fixture/skip_with_first_class_callable_self.php.inc b/rules-tests/DeadCode/Rector/ClassMethod/RemoveUnusedPrivateMethodParameterRector/Fixture/skip_with_first_class_callable_self.php.inc
new file mode 100644
index 00000000000..b8bcb2a56fe
--- /dev/null
+++ b/rules-tests/DeadCode/Rector/ClassMethod/RemoveUnusedPrivateMethodParameterRector/Fixture/skip_with_first_class_callable_self.php.inc
@@ -0,0 +1,16 @@
+<?php
+
+namespace Rector\Tests\DeadCode\Rector\ClassMethod\RemoveUnusedPrivateMethodParameterRector\Fixture;
+
+final class SkipWithFirstClassCallableSelf
+{
+    public static function run()
+    {
+        return self::validate(...);
+    }
+
+    private static function validate(string $attribute, mixed $value): bool
+    {
+        return $value === true;
+    }
+}
diff --git a/rules-tests/DeadCode/Rector/ClassMethod/RemoveUnusedPrivateMethodParameterRector/Fixture/skip_with_first_class_callable_self_in_instance_method.php.inc b/rules-tests/DeadCode/Rector/ClassMethod/RemoveUnusedPrivateMethodParameterRector/Fixture/skip_with_first_class_callable_self_in_instance_method.php.inc
new file mode 100644
index 00000000000..09b45c87a67
--- /dev/null
+++ b/rules-tests/DeadCode/Rector/ClassMethod/RemoveUnusedPrivateMethodParameterRector/Fixture/skip_with_first_class_callable_self_in_instance_method.php.inc
@@ -0,0 +1,16 @@
+<?php
+
+namespace Rector\Tests\DeadCode\Rector\ClassMethod\RemoveUnusedPrivateMethodParameterRector\Fixture;
+
+final class SkipWithFirstClassCallableSelfInInstanceMethod
+{
+    public function run()
+    {
+        return self::validate(...);
+    }
+
+    private function validate(string $attribute, mixed $value): bool
+    {
+        return $value === true;
+    }
+}
diff --git a/rules-tests/DeadCode/Rector/ClassMethod/RemoveUnusedPrivateMethodParameterRector/Fixture/skip_with_first_class_callable_static.php.inc b/rules-tests/DeadCode/Rector/ClassMethod/RemoveUnusedPrivateMethodParameterRector/Fixture/skip_with_first_class_callable_static.php.inc
new file mode 100644
index 00000000000..e092422b9a4
--- /dev/null
+++ b/rules-tests/DeadCode/Rector/ClassMethod/RemoveUnusedPrivateMethodParameterRector/Fixture/skip_with_first_class_callable_static.php.inc
@@ -0,0 +1,16 @@
+<?php
+
+namespace Rector\Tests\DeadCode\Rector\ClassMethod\RemoveUnusedPrivateMethodParameterRector\Fixture;
+
+final class SkipWithFirstClassCallableStatic
+{
+    public static function run()
+    {
+        return static::validate(...);
+    }
+
+    private static function validate(string $attribute, mixed $value): bool
+    {
+        return $value === true;
+    }
+}
diff --git a/src/NodeTypeResolver/PHPStan/Scope/PHPStanNodeScopeResolver.php b/src/NodeTypeResolver/PHPStan/Scope/PHPStanNodeScopeResolver.php
index 46a8b7a4e47..7e510d472e8 100644
--- a/src/NodeTypeResolver/PHPStan/Scope/PHPStanNodeScopeResolver.php
+++ b/src/NodeTypeResolver/PHPStan/Scope/PHPStanNodeScopeResolver.php
@@ -382,10 +382,6 @@ private function nodeScopeResolverProcessNodes(
 
     private function processCallLike(CallLike $callLike, MutatingScope $mutatingScope): void
     {
-        if ($callLike->isFirstClassCallable()) {
-            return;
-        }
-
         if ($callLike instanceof StaticCall) {
             $callLike->class->setAttribute(AttributeKey::SCOPE, $mutatingScope);
             $callLike->name->setAttribute(AttributeKey::SCOPE, $mutatingScope);
@@ -398,6 +394,10 @@ private function processCallLike(CallLike $callLike, MutatingScope $mutatingScop
             $callLike->class->setAttribute(AttributeKey::SCOPE, $mutatingScope);
         }
 
+        if ($callLike->isFirstClassCallable()) {
+            return;
+        }
+
         foreach ($callLike->getArgs() as $arg) {
             $arg->value->setAttribute(AttributeKey::SCOPE, $mutatingScope);
         }

From 212a6de2b7348dc889b00d2bc30d5d65b03c29af Mon Sep 17 00:00:00 2001
From: Philip Norton <philip@adam.co.za>
Date: Thu, 5 Nov 2026 10:43:16 +0200
Subject: [PATCH 2/2] [DeadCode] Skip private method used as array callable on
 removing unused parameter

The code receiving [self::class, 'method'], [static::class, 'method'] or
[$this, 'method'] decides how many arguments it passes, the same as with a
first-class callable. PrivateMethodParamRemover never looked at arrays, so
it removed the parameter.

It now keeps the parameter when an array in the class names the method, or
when ArrayCallableMethodMatcher cannot tell which method the array names.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
---
 ...with_array_callable_of_other_class.php.inc | 41 +++++++++++++++++++
 ...with_array_callable_dynamic_method.php.inc | 16 ++++++++
 ...array_callable_in_property_default.php.inc | 13 ++++++
 ...allable_required_constructor_param.php.inc | 20 +++++++++
 ...kip_with_array_callable_self_class.php.inc | 16 ++++++++
 ...p_with_array_callable_static_class.php.inc | 16 ++++++++
 .../skip_with_array_callable_this.php.inc     | 16 ++++++++
 .../PrivateMethodParamRemover.php             | 38 +++++++++++++++++
 8 files changed, 176 insertions(+)
 create mode 100644 rules-tests/DeadCode/Rector/ClassMethod/RemoveUnusedPrivateMethodParameterRector/Fixture/remove_with_array_callable_of_other_class.php.inc
 create mode 100644 rules-tests/DeadCode/Rector/ClassMethod/RemoveUnusedPrivateMethodParameterRector/Fixture/skip_with_array_callable_dynamic_method.php.inc
 create mode 100644 rules-tests/DeadCode/Rector/ClassMethod/RemoveUnusedPrivateMethodParameterRector/Fixture/skip_with_array_callable_in_property_default.php.inc
 create mode 100644 rules-tests/DeadCode/Rector/ClassMethod/RemoveUnusedPrivateMethodParameterRector/Fixture/skip_with_array_callable_required_constructor_param.php.inc
 create mode 100644 rules-tests/DeadCode/Rector/ClassMethod/RemoveUnusedPrivateMethodParameterRector/Fixture/skip_with_array_callable_self_class.php.inc
 create mode 100644 rules-tests/DeadCode/Rector/ClassMethod/RemoveUnusedPrivateMethodParameterRector/Fixture/skip_with_array_callable_static_class.php.inc
 create mode 100644 rules-tests/DeadCode/Rector/ClassMethod/RemoveUnusedPrivateMethodParameterRector/Fixture/skip_with_array_callable_this.php.inc

diff --git a/rules-tests/DeadCode/Rector/ClassMethod/RemoveUnusedPrivateMethodParameterRector/Fixture/remove_with_array_callable_of_other_class.php.inc b/rules-tests/DeadCode/Rector/ClassMethod/RemoveUnusedPrivateMethodParameterRector/Fixture/remove_with_array_callable_of_other_class.php.inc
new file mode 100644
index 00000000000..8c0fda45193
--- /dev/null
+++ b/rules-tests/DeadCode/Rector/ClassMethod/RemoveUnusedPrivateMethodParameterRector/Fixture/remove_with_array_callable_of_other_class.php.inc
@@ -0,0 +1,41 @@
+<?php
+
+namespace Rector\Tests\DeadCode\Rector\ClassMethod\RemoveUnusedPrivateMethodParameterRector\Fixture;
+
+final class RemoveWithArrayCallableOfOtherClass
+{
+    public function run()
+    {
+        $this->format('unused', 'value');
+
+        return [\DateTime::class, 'format'];
+    }
+
+    private function format(string $unused, string $value): string
+    {
+        return $value;
+    }
+}
+
+?>
+-----
+<?php
+
+namespace Rector\Tests\DeadCode\Rector\ClassMethod\RemoveUnusedPrivateMethodParameterRector\Fixture;
+
+final class RemoveWithArrayCallableOfOtherClass
+{
+    public function run()
+    {
+        $this->format('value');
+
+        return [\DateTime::class, 'format'];
+    }
+
+    private function format(string $value): string
+    {
+        return $value;
+    }
+}
+
+?>
diff --git a/rules-tests/DeadCode/Rector/ClassMethod/RemoveUnusedPrivateMethodParameterRector/Fixture/skip_with_array_callable_dynamic_method.php.inc b/rules-tests/DeadCode/Rector/ClassMethod/RemoveUnusedPrivateMethodParameterRector/Fixture/skip_with_array_callable_dynamic_method.php.inc
new file mode 100644
index 00000000000..1b6a4d33298
--- /dev/null
+++ b/rules-tests/DeadCode/Rector/ClassMethod/RemoveUnusedPrivateMethodParameterRector/Fixture/skip_with_array_callable_dynamic_method.php.inc
@@ -0,0 +1,16 @@
+<?php
+
+namespace Rector\Tests\DeadCode\Rector\ClassMethod\RemoveUnusedPrivateMethodParameterRector\Fixture;
+
+final class SkipWithArrayCallableDynamicMethod
+{
+    public function run(string $method)
+    {
+        return [$this, $method];
+    }
+
+    private function validate(string $attribute, mixed $value): bool
+    {
+        return $value === true;
+    }
+}
diff --git a/rules-tests/DeadCode/Rector/ClassMethod/RemoveUnusedPrivateMethodParameterRector/Fixture/skip_with_array_callable_in_property_default.php.inc b/rules-tests/DeadCode/Rector/ClassMethod/RemoveUnusedPrivateMethodParameterRector/Fixture/skip_with_array_callable_in_property_default.php.inc
new file mode 100644
index 00000000000..0f327aa51a0
--- /dev/null
+++ b/rules-tests/DeadCode/Rector/ClassMethod/RemoveUnusedPrivateMethodParameterRector/Fixture/skip_with_array_callable_in_property_default.php.inc
@@ -0,0 +1,13 @@
+<?php
+
+namespace Rector\Tests\DeadCode\Rector\ClassMethod\RemoveUnusedPrivateMethodParameterRector\Fixture;
+
+final class SkipWithArrayCallableInPropertyDefault
+{
+    public array $callback = [self::class, 'validate'];
+
+    private static function validate(string $attribute, mixed $value): bool
+    {
+        return $value === true;
+    }
+}
diff --git a/rules-tests/DeadCode/Rector/ClassMethod/RemoveUnusedPrivateMethodParameterRector/Fixture/skip_with_array_callable_required_constructor_param.php.inc b/rules-tests/DeadCode/Rector/ClassMethod/RemoveUnusedPrivateMethodParameterRector/Fixture/skip_with_array_callable_required_constructor_param.php.inc
new file mode 100644
index 00000000000..47fd0505188
--- /dev/null
+++ b/rules-tests/DeadCode/Rector/ClassMethod/RemoveUnusedPrivateMethodParameterRector/Fixture/skip_with_array_callable_required_constructor_param.php.inc
@@ -0,0 +1,20 @@
+<?php
+
+namespace Rector\Tests\DeadCode\Rector\ClassMethod\RemoveUnusedPrivateMethodParameterRector\Fixture;
+
+final class SkipWithArrayCallableRequiredConstructorParam
+{
+    public function __construct(private string $name)
+    {
+    }
+
+    public function run()
+    {
+        return [self::class, 'validate'];
+    }
+
+    private static function validate(string $attribute, mixed $value): bool
+    {
+        return $value === true;
+    }
+}
diff --git a/rules-tests/DeadCode/Rector/ClassMethod/RemoveUnusedPrivateMethodParameterRector/Fixture/skip_with_array_callable_self_class.php.inc b/rules-tests/DeadCode/Rector/ClassMethod/RemoveUnusedPrivateMethodParameterRector/Fixture/skip_with_array_callable_self_class.php.inc
new file mode 100644
index 00000000000..b02329632ff
--- /dev/null
+++ b/rules-tests/DeadCode/Rector/ClassMethod/RemoveUnusedPrivateMethodParameterRector/Fixture/skip_with_array_callable_self_class.php.inc
@@ -0,0 +1,16 @@
+<?php
+
+namespace Rector\Tests\DeadCode\Rector\ClassMethod\RemoveUnusedPrivateMethodParameterRector\Fixture;
+
+final class SkipWithArrayCallableSelfClass
+{
+    public static function run()
+    {
+        return [self::class, 'validate'];
+    }
+
+    private static function validate(string $attribute, mixed $value): bool
+    {
+        return $value === true;
+    }
+}
diff --git a/rules-tests/DeadCode/Rector/ClassMethod/RemoveUnusedPrivateMethodParameterRector/Fixture/skip_with_array_callable_static_class.php.inc b/rules-tests/DeadCode/Rector/ClassMethod/RemoveUnusedPrivateMethodParameterRector/Fixture/skip_with_array_callable_static_class.php.inc
new file mode 100644
index 00000000000..fcd53a1062d
--- /dev/null
+++ b/rules-tests/DeadCode/Rector/ClassMethod/RemoveUnusedPrivateMethodParameterRector/Fixture/skip_with_array_callable_static_class.php.inc
@@ -0,0 +1,16 @@
+<?php
+
+namespace Rector\Tests\DeadCode\Rector\ClassMethod\RemoveUnusedPrivateMethodParameterRector\Fixture;
+
+final class SkipWithArrayCallableStaticClass
+{
+    public static function run()
+    {
+        return [static::class, 'validate'];
+    }
+
+    private static function validate(string $attribute, mixed $value): bool
+    {
+        return $value === true;
+    }
+}
diff --git a/rules-tests/DeadCode/Rector/ClassMethod/RemoveUnusedPrivateMethodParameterRector/Fixture/skip_with_array_callable_this.php.inc b/rules-tests/DeadCode/Rector/ClassMethod/RemoveUnusedPrivateMethodParameterRector/Fixture/skip_with_array_callable_this.php.inc
new file mode 100644
index 00000000000..0465c4d8ad4
--- /dev/null
+++ b/rules-tests/DeadCode/Rector/ClassMethod/RemoveUnusedPrivateMethodParameterRector/Fixture/skip_with_array_callable_this.php.inc
@@ -0,0 +1,16 @@
+<?php
+
+namespace Rector\Tests\DeadCode\Rector\ClassMethod\RemoveUnusedPrivateMethodParameterRector\Fixture;
+
+final class SkipWithArrayCallableThis
+{
+    public function run()
+    {
+        return [$this, 'validate'];
+    }
+
+    private function validate(string $attribute, mixed $value): bool
+    {
+        return $value === true;
+    }
+}
diff --git a/rules/DeadCode/NodeManipulator/PrivateMethodParamRemover.php b/rules/DeadCode/NodeManipulator/PrivateMethodParamRemover.php
index 7d1d386020a..a41a0e38883 100644
--- a/rules/DeadCode/NodeManipulator/PrivateMethodParamRemover.php
+++ b/rules/DeadCode/NodeManipulator/PrivateMethodParamRemover.php
@@ -5,6 +5,7 @@
 namespace Rector\DeadCode\NodeManipulator;
 
 use PhpParser\Node;
+use PhpParser\Node\Expr\Array_;
 use PhpParser\Node\Expr\MethodCall;
 use PhpParser\Node\Expr\StaticCall;
 use PhpParser\Node\Identifier;
@@ -16,9 +17,13 @@
 use Rector\BetterPhpDocParser\PhpDocInfo\PhpDocInfoFactory;
 use Rector\BetterPhpDocParser\PhpDocManipulator\PhpDocTagRemover;
 use Rector\Comments\NodeDocBlock\DocBlockUpdater;
+use Rector\NodeCollector\NodeAnalyzer\ArrayCallableMethodMatcher;
+use Rector\NodeCollector\ValueObject\ArrayCallable;
+use Rector\NodeCollector\ValueObject\ArrayCallableDynamicMethod;
 use Rector\NodeNameResolver\NodeNameResolver;
 use Rector\NodeTypeResolver\NodeTypeResolver;
 use Rector\PhpParser\Node\BetterNodeFinder;
+use Rector\PHPStan\ScopeFetcher;
 
 final readonly class PrivateMethodParamRemover
 {
@@ -29,6 +34,7 @@ public function __construct(
         private BetterNodeFinder $betterNodeFinder,
         private NodeNameResolver $nodeNameResolver,
         private NodeTypeResolver $nodeTypeResolver,
+        private ArrayCallableMethodMatcher $arrayCallableMethodMatcher,
     ) {
     }
 
@@ -73,6 +79,11 @@ private function removeCallerArgs(Class_ $class, ClassMethod $classMethod, array
             return false;
         }
 
+        // the code receiving the callable decides how many arguments it passes
+        if ($this->isUsedAsArrayCallable($class, $classMethod)) {
+            return false;
+        }
+
         $keysArg = array_keys($paramsToRemove);
 
         $classObjectType = new ObjectType((string) $this->nodeNameResolver->getName($class));
@@ -112,6 +123,33 @@ private function removeCallerArgs(Class_ $class, ClassMethod $classMethod, array
         return true;
     }
 
+    private function isUsedAsArrayCallable(Class_ $class, ClassMethod $classMethod): bool
+    {
+        $scope = ScopeFetcher::fetch($class);
+        $methodName = $this->nodeNameResolver->getName($classMethod);
+
+        /** @var Array_[] $arrays */
+        $arrays = $this->betterNodeFinder->findInstanceOf($class, Array_::class);
+
+        foreach ($arrays as $array) {
+            $arrayCallable = $this->arrayCallableMethodMatcher->match($array, $scope, $methodName);
+            if ($arrayCallable instanceof ArrayCallableDynamicMethod) {
+                return true;
+            }
+
+            if (! $arrayCallable instanceof ArrayCallable) {
+                continue;
+            }
+
+            if ($this->nodeNameResolver->isName($class, $arrayCallable->getClass())
+                && $this->nodeNameResolver->isName($classMethod, $arrayCallable->getMethod())) {
+                return true;
+            }
+        }
+
+        return false;
+    }
+
     /**
      * @param int[] $keysArg
      */